Only took about a year for it to happen. How long til it crashes? https://www.theguardian.com/technology/2018/mar/20/child-abuse-imagery-bitcoin-blockchain-illegal-content …https://twitter.com/RichFelker/status/844957056188764160 …
It might have been legend but I don't think anyone had credible claims of their truth. Proof would require the keys. And once the keys are out they're sufficiently tiny that stopping spread or accountability for ownership is impossible.